The invention relates to a device for feeding a processing section with printed products, in particular folded or non-folded printed sheets. Such a device includes a magazine and a feeding mechanism which is provided with gripping means and conveying means for removing the printed products from the magazine and feeding them to the processing section.
A device of this type is disclosed, for example, in European Patent Application EP-1 186 558 A, co-owned by the assignee of the present application, where folded or non-folded printed products are withdrawn from a stack with the aid of a rotating drum and are then supplied to a collecting channel. The printed products are supplied directly, without change in direction, to the collecting channel. The device operates based on the so-called principle of withdrawal in longitudinal direction, wherein the withdrawal direction is also the transporting direction of the processing section. The printed sheets are used to produce books, brochures, magazines or similar printed products.
The mechanical configuration of such a device is generally based on the configuration for a drum feeder with individual drive. The drum circumference essentially corresponds to the division for the processing section, e.g. a gathering chain. Processing sections of this type are used, for example, for producing books in adhesive binding machines. Standard divisions for such processing sections are 24″ and 18,″ but other divisions such as a 20″ division are possible as well. With a 24″ division, the drum circumference is normally 200 mm and the production output is approximately 15'000 cycles/hour. A correspondingly higher production output of 18'000 cycles/hour is standard for a processing section with 18″ collecting chain and 18″ drum feeder. If a plant has adhesive binding machines with different chain divisions, for example 24″ and 18,″ correspondingly different drum feeders, in this case 24″ and 18″ drum feeders, are required for the optimum production capacity, so that the circumferential speed of the drum corresponds to the respective chain speed.
A device for a 24″ collecting chain could be adapted to an 18″ chain by installing a delay drive to achieve a correspondingly higher production output. The delay drive would have to be adjusted so as to adapt the transfer of the printed products to the division and speed of the processing section. The rotating driving device and/or the withdrawing drum would have to start at the slower speed, but would then have to be accelerated so that the following withdrawal operation could again start synchronized with the cycle. A speed change of this type, however, would endanger the process safety. Alternatively, the withdrawal drum could also be replaced with a drum having a smaller diameter. However, with a smaller drum diameter, e.g. 150 mm, the disadvantage would be that accommodating the gripping organ and the required mechanical elements would be difficult.